remove importposts.py from tests. no longer needed
pass in blog to pull method instead of self
cleaner backend testing implementation
rename mock_dropbox.py to mock_backends.py
slugify post title in test factory
add MockLocalFileBackend to mock_backends
use join to get the full path of the filename when
opening. this helps when testing with tempfile

check for 'stardate' key in remote_post dict

execpt KeyError if a remote_post doesn't exist yet
only add parsed post to parsed_list if there is
something to add

previously, self.parse() was returning {} to the
remote_post list causing KeyErrors when passed to
the FileParser
adds initial testing for LocalFileBackend